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Heat Wave Shuts Down Alabama Reactor
mdsolar writes "In a first for the US, one of three nuclear reactors at the Browns Ferry nuclear plant in Alabama has been shut down because the Tennessee River is too hot to provide adequate cooling for the waste heat produced by the reactor. This is happening as the TVA faces its highest demand for power ever, reports the Houston Chronicle. This effect has been seen in Europe in the past, forcing reduced generation, but the US has until now been immune to the problem. The TVA will buy power elsewhere and impose higher rates, blaming reduced river flow as a result of drought."
As for a while, they were planning to use one engineer's idea of cooling it with ice cold beer.
In Soviet Russia, overheating nuclear reactor shuts down YOU!
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>but the US has, until now, been immune to the problem.
no, not immune. it just hasn't happend until now.
I work at a nuclear power plant. We have a limit for the temperature of the river downstream of our returned cooling water for environmental reasons, not reasons related to the power generation process. I suspect the TVA has a similar requirement.
I noted from the nrc website (www.nrc.gov) that their other reactors are operating at reduced load, which is what our reactors must do to limit the heat input into the river.
So this is nothing remarkable.
Why not just run the river through a refrigerator to cool it down? After all, you can generate the electricity for the refrigerator in the plant.
(I'd patent the idea, but the patent office has a silly rule regarding perpetual motion machines that gets in the way...)
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This is not that unusual for power plants. Some coal fired units are off as well, for example Dynegy's Wabash River is currently experiencing similar problems. Obviously this hurts everyone (the company loses generation during times when wholesale power prices are high and, if load gets too high, the consumer might experience brown outs or black outs). This problem will likely get worse as well as global warming takes hold.
To anyone arguing that Climate Change is actually a good thing - in general, it isn't, and this is an example. Especially in the US, our entire infrastructure, agriculture and manufacturing is built and created under the assumption that things will stay the same. Pipelines in Alaska were built under the assumption that permafrost was, well, permanent. Nuclear reactors were built under the assumption that the temperature changes of rivers are known and won't change. Levies are built with certain assumptions about local rainfall. Agriculture is built on certain assumptions about the local weather.
Yes, we can adapt to it, but it's an expensive proposition. All the stuff about cities flooding, people dying and malaria becoming the new bane of the US is extreme cases being blown up to make good news stories. It's the accumulation of small things like this that'll hurt.
Those who can, do. Those who can't, sue.
It ain't about problems with the cooling itself, for that the rivers would need to be far hotter. The problem is enviromental, if you add extra heat to an already warm river you risk that it rises to the point were you destroy the eco-system. Simply put, the fishes get cooked and the algea grow out of control.
This is considered to be a bad thing.
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You may solo them, I prefer them in a group.
The cooling problem is a result of TVA's interest in building more reactors. Browns Ferry is now operating with two reactors instead of three because they recently added a reactor. They are also planning on adding a reactor upstream at Watts Bar http://www.tva.gov/news/releases/julysep07/wbu2.ht m adding to the heat load on the Tennessee River. So, next time, they may have to take two Browns Ferry reactors off line at seasonal peak demand. This makes electricity more expensive because it requires buying rather than selling electricity when it is most expensive.
s -selling-solar.html
But, the fairly natural solution to the problem, reducing summer demand through net metering of customer generated solar power, a solution being implemented in 41 states and DC, is hampered in the TVA service territory by TVA's net metering policy: http://www.tva.gov/purpa/net_metering.htm which is a billing period-by-billing period policy rather than an annual carryover policy used in net metering states. Adopting a reasonable net metering policy would allow TVA to become a summer time peak demand power exporter and gain by arbitrage, reducing the risk of higher overall rates it is building for itself by not paying attention to the capacity of the river system to handle the 60% of wasted energy nuclear power generation creates.
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Because "heat" is the most difficult form of energy to convert to other forms. Not difficult in an engineering sense, but difficult from a basic thermodynamics perspective. In order to convert heat into another form of energy, you have to have a reservoir available with lower heat density -- temperature. Otherwise your process won't spontaneously go (and that's the problem with energy; non-spontaneous conversion to another form only _appears_ non-spontaneous; thermodynamics guarantees that you've just overlooked a pathway in which the energy is being converted to a "less useful", or higher entropy, form). In this case, the reservoir with lower heat density (the river) doesn't have low _enough_ heat density (or it's restricted by environmental concerns).
That's just what the TVA is having problems with. After all, nuclear plants essentially use the heat produced by degrading high quality nuclear energy to lower quality steam or the equivalent. This is allowed to degrade to even lower quality by taking a steam jet with well-defined momentum, and impacting it on a turbine. After the turbine (producing electricity, etc.), the steam has almost no quality, and perhaps can be used for secondary heating purposes. At this stage, you have to get rid of the still-high-temperature but low quality steam, and they do that by rejecting the heat into the river.
Interesting in the article that the journalist doesn't include power generated by hydroelectric dams as renewable energy...
"TVA gets about 60 percent of its electricity from coal-fired power plants, 30 percent from nuclear plants and 10 percent from its 29 hydroelectric dams. Renewable energy sources such as wind and solar account for less than 1 percent."
Any idea why that might be? Political slant? ignorance?
Umm, I mean the water flows through the dam, it goes out to sea, it evaporates, and it rains back up in the mountains and comes through the dam again. Seems pretty renewable to me.... at least some of it is coming back up through that cycle if not all...
To give you an example. Someone starts screaming in public that they are going to kill you. They show up at your house with a large handgun and force the door. A couple minutes later, several shots are heard. The man runs out of your house without the handgun. You are found dead and the coroner determines the hour of your death to be around the time the man with the handgun showed up at your door. Noone else has shown up that day other than the man with the handgun. The bullets which have blasted what little brains you have out the back of your head are determined to come from the gun lying on the floor, which is the same one brought in by the man who forced his way into your house.
Now, given all this, you would apparently parrot the rule saying "Correlation is not causation".
I feel like death on a soda cracker.
If only it were that simple.
Imagine one of those old-style water wheels. Your question is akin to asking, "Why not figure out a way to use the energy of that flowing water without wasting it by allowing it to flow away?"
Why not just pump it into a giant tower and we can all have hot water despite the jackass taking a 2hr shower!!!!
Work for Pay and Pay for Freedom
To heat domestic water, space heating and even to power adsorption chillers which can reduce AC requirements. Even coal power stations can hit 88% efficient.
t s.html
... Well you decide for yourself.
http://www.helsinginenergia.fi/en/tuotanto/benefi
US power stations are still only 40% efficient because
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The bicycle as a commuter vehicle works only under ideal conditions and only for the young and fit. You won't be taking a bicycle into Buffalo, NY in mid-winter. You won't be taking a bicycle into Houston, TX in mid-summer.
I would hope you would parrot the rule saying "Correlation is not causation", or rather I would hope that any other alternatives are also investigated (like suicide or possibly even that a third person did the shooting) sure Its unlikely, but its worth the effort to prevent a miscarriage of justice.
How this applies to climate change though isn't all that clear. We are sure that temperatures are rising, we are fairly sure that they will continue to rise, and we are inclined to believe that the changes are brought about by our own actions. In that scenario we need to tackle what is apparent whilst also making sure that there are no other explanations.
Much like you would arrest the potential murderer in your first example immediately and then discount any other possibilities, we should be looking to tackle climate change (by addressing the issues we believe cause it) until we know more one way or the other, what we should not do is close down any other avenues of investigation until we are sure that we have all the information we need, after all if something else turns out to be the culprit (regardless of how unlikely that is) we may need to take some other action, something we couldn't do if we stopped looking.
It's really amazing that these basic principals of thermodynamics were all figured out in the early 1800s, but almost 200 years later people still don't get it.
No, dear, I did not. You are struggling with the Second Law of Thermodynamics, which — in the form most applicable to the situation — is spelled as "It is impossible to convert heat completely into work."
My point was, that a better-engineered reactor would convert more energy into work. This increase of the work/heat ratio is a purely engineering problem — the only "fundamental limit of thermodynamics" is that the ratio be below 1...
In Soviet Washington the swamp drains you.
Of course, you're welcome to study thermodynamic engineering and try to circumvent this issue yourself. If you manage to pull it off, you could make $Billions.
If the temperature of your cooling medium is 50 fahrenheit (280 Kelvin)
Your process can never be more than 47% efficient. No amount of engineering can change this fact.
Now if the temperature of your cooling medium rises to 90 fahrenheit, then you are stuck below 42%.
Thermodynamics not only says that the ratio must be below 1, it also says exactly by how much it must be below 1.
Sure. Now if only someone in Alabama living close to the power plant needed to heat his house in the middle of a heat wave...
"Before air conditioning, yankees stayed in yankeeland. After air conditioning they moved to places where they weren't welcome."
Actually, refrigeration technology took off in the South before the North. The Yankees you so deride didn't need large plants to manufacture ice for their iceboxes, they had the Great Lakes.
As for electricity generation, you'll note that the New Deal and the Tennessee Valley Authority (TVA in TFA) was interested in improving electricity generation in the South long before consumer air conditioning was available, let alone viable. Southerners were interested in those new-fangled electric lights Northerners were beginning to take for granted.
"We used clothes lines to hang and dry our clothes, not electric driers."
Another technology that caught on in the South more than the North. It's not the North that has to deal with trying to dry clothes in 157% humidity, at least not year-round.
A nuclear reaction can produce much higher temperatures than that. Finding a good medium, and a good way to contain/control the reaction is an engineering problem.
Uhm, no, it does not. The equation you are referring to is an engineering one. It applies to a single round heat/work conversion. As the "spent" medium is hotter than fresh (and it always is), its heat could be used again in another cycle. And so on (assuming "endless" supply of fresh medium, which river provides), until the difference in temperatures make another cycle impractical. This is how efficiency can — in theory — be brought all the way up to 1 but not quite.
I don't think, the existing plants do even one more cycle because of all the engineering problems involved. Some use the "spent" hot water to heat up nearby buildings and/or orchards... Making these uses (of heat) more efficient is another problem — a lot of the heat-derived electricity is converted back to heat by, uhm, electric heaters, as well as grills and other cooking machinery. But that's a subject for another flame-war...
In Soviet Washington the swamp drains you.
I have supported the restarting of Browns Ferry Unit 1 for a long time. Because despite the issues nuclear power is an immediatly available and fairly clean power source. Browns Ferry Unit 1 has had a bumpy road to travel since it was commissioned, and then shut down, and then restarted. Since its restart it has contributed clean energy at a time when the Tennessee Valley has been hammered by record high temperatures.record rainfall deficits that have severely curtailed hydroelectric production and made for conditions calling for record power demand levels.
One occurance that also recently occured at Browns Ferry was the automatic shutdown of the reactor due to a coolant leak. TVA reported to the NRC that an unknown amount of reactor cooling water had indeed leaked and they spent last weekend repairing it. After restart the high water temps forced this shutdown. In fact this is nothing new though. We had the Sequoyah reactor using its cooling towers last year due to elevated water temps.
But yeah its been hot for sure. Also of interest is it looks like we are going to get the newest reactor in the US and that it be at Watts Bar. Unit 1 has been online there since 1996, and produces enough juice for 250,000 homes. Unit 2 at Watts Bar was roughly 80% complete when construction stopped. TVA is currently and exploring finishing the construction of Unit 2 giving us yet another clean power source. In September 2000 Watts Bar Unit 1 set a record for continuous operation of TVA reactors of similar design.
It's renewable in some sense, but not others. More specfically, big hydro genereally ends up not being sustainable:
fish spawning, methane, changes to the microclimate. On the other hand, we've not done enough with run-of-river.
Were that I say, pancakes?
"The South never had a "carbon footprint" before yankee glutons moved to Miami and Atlanta."
It sure burned the heck out of wood, Bo! The spelling is "Yankee gluttons", BTW.
"Most of us grew up without air conditioning and were happy that way. We used clothes lines to hang and dry our clothes, not electric driers. Life was good."
HAHAHAHA! When I see local folks volunteering to go back to an AC-free life I'll buy the connection between "no AC" and "happiness".
I still use clothes lines to dry clothes (clothes smell fresher besides the energy savings), but there is good reason AC is popular among non-Yankees. I don't see any nostalgia for doing washing in wooden tubs and ironing it with (aptly named) "sad irons" either. The tubs are planters and the irons are doorstops, the shotgun shacks whose layout helped somewhat with cooling are empty, and (most) of the people don't look the the folks in a James Agee book.
I'm a "Damn Yankee" (the ones that came and stayed) myself, though I'm far more genuinely countrified (and right wing) than most locals.
If you wanted to keep out the sort of Yankees that wouldn't fit, not selling them everything at fire-sale prices would have done it. The Southeast got rich and is getting richer by urban and suburban sprawl, so if ya want things the way they used to be, move into the Deep South and away from the coast.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
fish spawning, methane and changes to the micro climate don't effect the dam's ability to generate electricity, so it is still renewable energy.
Renewable != earth loving hippy compatible.
What if Tetris was invented by Nazis?
Your open-cycle system will never be more efficient than a carnot cycle at the same temperatures.
I'm afraid Wonko's right. The total efficiency converges to Carnot's. If there is any *usable* waste heat left at the end of a cycle to put into another heat engine, then the first cycle wasn't running at full (reversible) Carnot efficiency.
BTW, if a heat engine were ever to be used in a closed system, then its efficiency would quickly converge to 0%, since the hot source would cool down and the cold source would heat up! The Carnot cycle, as I said in my other post, assumes infinite, constant temperature hot and cold sources, i.e. effectively the same as a system where heat is constantly added to the hot source (by a nuclear reactor) and taken away from the cold source (by a running river) to maintain a constant temperature.
What's purple and commutes? An Abelian grape.
A little noted fact of the cold war is that a very large amount of the US total electrical generation capacity is in the TVA region (Tennessee River - Dependent) The loss of this reactor is serious as the whole USA has no reserve capacity at peak load and with the heat wave over the East USA this is a critical loss. If it were the only reactor in danger this might be of no concern. The US TVA operates 5 big reactors and numerous coal fired plants all of which have the Tennessee River at thermal capacity to cool them and the river is dropping daily.
If heavy sustained rain does not fall on the Tennessee River Valley over the next 3 to 4 months an event which is historically unlikely, the loss of something close to 15 times the Browns Ferry reactor in capacity is likely to hit the USA. There is nothing to pick up the load. The loss of this one reactor is nearly equal to all the wind energy the USA generates. This loss threatens the operations of every one of the 48 US States. With the possible loses in Alabama Power pools and their reactors etc as well as Georgia Power, this poses the very real risk of cutting the energy supply of the USA by a very large fraction. As I write the North Alabama region is short 60 inches of rain over the past 18 months. The US TVA has been drawing down storage for 5 years now. There is no reserve and little prospect of one for some years to come.
I had warning of this imminent event when the City of Huntsville requested from TVA more water for its treatment plant and was turned down for supply. I knew then that the supply was gone.
Never Politically Correct ~ I prefer the facts If you don't like what I say, get a life, or comment yourself.
Generally they don't transport steam, they transport hot but liquid water. See, engineers are not idiots. You must be new here.
Terrorists can't threaten a country's freedom and democracy. Only lawmakers and voters can do that.
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Mi - Wonko and SMNW are both right and know their Carnot cycle, thermodynamics, etc.
If you want to continue to beat this dead horse, I think your best bet would be to educate yourself about thermodynamics, the Carnot cycle, and what it means to have inifinite temperature reservoirs.
Just as real world efficiencies can only approach the Carnot cycle, your answers can only approach the previous postings as you learn more about what you are talking about.
You need to google "Maxwell's Demon."
The reactor was shut down because the water exiting the plant's cooling system exceeded an average of 90 degrees F over a 24 hour period. The plants have an agreement with the state to limit the temperature of the water they put into the river. The water in the river is not even remotely 90 degrees F.
Brown's Ferry also just recently started one of its reactors after a long downtime, so this only kicked us back a few months. It's not a big impact to the nation's grid, not even to the local area.
As for why we don't recapture the energy in the heated water to make even more power, well, they just didn't think it was necessary back when we used to build power plants back in the 60's. Investing money in anything nuclear in the US is political suicide.
Using this to impeach nukes is profoundly wrong.
I'm in favor of alternative, renewable energy sources, but each source has varying degrees to which it is useful in particular situations for technology and production cost reasons. (For example, many places just don't make a good wind farm - and some places make an extremely mediocre and very expensive one.) I think we're going to have a bloom of much better solar at some point, but there's definitely still some room for improvement there.
I'm also certainly not supporting the current federal administration's energy policy, and I certainly do agree that a greater mix of power would be better.
However - despite repeatedly building coal fired plants that release literal tons of radioactive (definitively cancer causing) uranium into our air to be sucked up into our lungs - we're so afraid of anything called nuclear that to my knowledge we haven't issued a license to create a new nuclear plant in many years. I think we should wipe that kind of pollution from the map with large and increasing taxes that are specifically based on the pollution released. The only way we're going to do that in the short term would be to use more nuclear, not less, in combination with many other technologies.
So a lack of capacity is certainly not nuclear technology's fault. A reasonable answer to the GPs fears would be to have nuclear capacity spread out a little more so it wasn't so easily susceptible to drought, ANOTHER reasonable defense would be to have simply more average capacity, and a third defense would be to make plants which are more efficient - which would undoubtedly happen if we compared one we might build now to one decades old. Just look at the efficiency of cars from a similarly long time ago.
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